Color printing



Sept' 23. 9 192a G. H. BROWN COLOR PRINTING Filed April 12 m .11. liil ihipial I NI Patented Sept. 23, 1924.

UNITED STATES I GEORGE H. BROWN, OF CAMBRIDGE, MASSACHUSETTS.

COLOR PRINTING.

Application filed April 12, 1922. Serial No. 551,848.

To all whom it may concern Be it known that I, GEORGE H. BROWN, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented cer tain new and useful Improvements in Color Printing, of which the following is a specification.

This invention relates to processes and apparatus for printing, and is particularly concerned with printing in colors.

The usual method of producing printed matter that involves a plurality of colors requires the use of a separate plate engraved, etched, or the like, for each color appearing in the finished .work. The high portions of the plate receive ink from the inking rollers, and when the sheet of paper to be printed is pressed against the plate upon the closure of the platen of the press, the high parts of the plate deposit the ink previously applied to them on the paper sheet. Where several colors are to be used it is necessary to use a relief pattern or plate of the character just described for each color to be applied. These plates must be made very accurately and, consequently, they are relatively expensive to manufacture and they require considerable time to prepare. This process therefore not only involves a substantial outlay for plates, but it also necessitates considerable delay in starting the actual printing operations on a given piece of work. 7

The present invention aims todevise a. process and apparatus applicable to a great variety of kinds of printed work in which both the expense and the time involved in preparing for the printing of a given piece of work whether to be done in one or more colors, will be substantially reduced.

It is proposed to accomplish this object by utilizing, the peculiar qualities of abra sive or roughened surfaces, such as the surfaces of sand paper, emery cloth, and the like, hereinafter referred to as sand paper, in taking ink and applying it.

The nature of the invention will be readily understood from the following description when read in connection with the accompanyin drawings, and the novel features will be particularly pointed out in the appended claims.

In the drawings,

Figure 1 is a perspective view showing parts of a printing press of a well known form, but including apparatus embodying the present invention;

Fig. 2 is a perspective view showing the manner in which the ink is applied,

Fig. 3 is a cross sectional view, greatly magnified, illustrating the method of applying the ink to the abrasive surfaces;

Fig. 4 is a view of a magnified cross section of the abrasive surface that receives the ink; I

Fig. 5 is a cross sectional view showing the manner in which a sheet to be printed is pressed against the abrasive surface previously inked;

Fig. 6 is a cross sectional view similar to Fig. 5, but on a larger scale, showing the manner in which the ink is transferred from the abrasive surface to the paper sheet and results in printing the sheet;

Fig. 7 is a view similar to Fig. 6 showing the effect produced by an overlay having a-wavy surface; and

Fig. 8 is a plan vievi of a printed sheet.

Referring first to Fig. 1, 2 designates the chase or type frame, 3 the platen, and 4 the inking roll of a printing press of the ordinary and well known form. arrangement shown a plate 5 is mounted in the chase 2 and a sheet of sand paper 6 is glued, or otherwise secured, to the face of the. plate 5. When the inking roller 4 rolls over the sanded face of the sheet 6 it In the r applies ink to the particles of sand or equivalent abrasive material on the paper. Due to the yielding character of the roller 4 and to the peculiar characteristics of these particles of abrasive material, the particles do not take the ink on the ends of their points, but do receive ink on the sides of these particles. This is very well illustrated in Fig. 4 in which the sand particles, greatly enlarged, are shown at 7. It will be observed that they hold practically no ink on their points but that the, amount of ink taken up by them increases from their points toward their bases. In other words, the sides of these particles are heavily coated with ink while their points are devoid of ink.

The sheet of paper 8, or other material to be printed, is held in suitable guides on the platen 3 and is supported or backed by a form or overlay 9. This overla may consist simply of a sheet of cardboar or other suitable material, cut to the shape which it is desired to reproduce on the printed sheet. When the platen of the press closes, the overlay 9 presses the areas of the sheet 8 which are superposed thereon against the inked surface of the sand paper sheet 6, and these parts, therefore, receive ink from the sanded surface and are printed. The other portions of the sheet, however, mrely rest lightly against the points of the particles of sand and do not receive ink. The result, in the particular instance shown, is the production of a printed area somewhat like that indicated at 10 in Fig. 8, this area representing the background, in a given color, of a picture, the other parts of which can be printed by the same process in subsequent operations.

By using an overlay havin a wavy surface, as indicated at 12, Fig. certain portions of the sheet will be pressed against the abrasive surfaces more firmly than others and therefore will receive a greater quantity of ink, with the result that intermediate color tones will be produced on the printed sheet.

The nature of the surface printed in this manner can be varied as desired, within wide limits, by properly selecting the grade of sand paper or equivalent material used, a sq'ppled effect being produced by relatively coarse grades, and a substantially uniform surface being produced by the finer grades.

It will be understood that a separate form or overlay is used for each color, theoverlay being shaped to effect the printing of the desired area with the appropriate color. The mani ulation in this respect is not essentially iflerent from that of the present posters, advertisements,

methods.

This process and apparatus is of particular. utility in job printing where the finer effects that necessitate the use of engraved plates are not required. It is simply necessary here to secure the proper grade of sand paper, mount it on a supportin plate, make the proper cut outs or overTays, and go ahead with the printing process. All of these preliminary operatlons obviously can be erformed very quickly and very economica 1y. This process is particularly valuable for many classes of rinted matter such as and a great variety of other work which the job printeris required to handle both because it saves the expense which otherwise would be required inmaking plates, and also because it eliminates the time lost in waiting for the lates to beprepared. The color effects r0 need in this manner have a pleasing c aracter, usually somewhat different from those produced by the usual processes, but for a great many purposes even more attractive than those obtained by the use of plates.

Having thus described my invention, what I desire to'claim as new is:

1. That improvement in the art of printing which consists in applying ink to a surface covered with particles of sharp sand, and then pressing the portionof the sheet which is to receive the ink against said particles.

2. .That improvement in the art of printing-which consists in applying ink with a yieldingly faced tool to a surface covered with particles of sharp sand, and then pressing the parts of the sheet to which the ink is to be applied against said particles.

3. That improvement in the art of printing which consists in rolling the ink on to a suitably mounted sheet of sand paper with a yielding roller whereb the ink is applied more liberally to the si es of the articles of sand on said paper than to the points of said particles, and pressing a ainst said inked surface the parts of the s eet to which the ink is to be applied, whereb said parts of the sheet will receive ink through contact with the sides of the abrasive particles.

4. That improvement in the art of printing which consists in mounting a sheet of sand paper on a suitable surface, inking the sanded face of said paper while causin the ink to adhere to the sides of the partic es of sand in said surface but leaving the points of said particles substantially free of ink, and pressin the sheet of material to be printed agalnst said inked surface with a form which localizes the pressure on the area of the sheet to which it is desired to apply the ink.

5. That improvement in the art of printing which consists in mounting a sheet of sand paper on a suitable surface, inking the sanded face of said paper while causing the ink to adhere to the sides of the particles of sand in said surface but leaving the points of said particles substantially cc of ink, and pressing a ainst said inked surface only the area of a s eet to which it is desired to apply the ink.

6. That improvement in the art of printing which consists in mounting a sheet of sand paper on a suitable surface, inking the sanded ace of said pa r while-causin the ink to adhere to the si es of the partic es of sand in said surface but leaving the )inta of said particles substantially ree o ink, pressin against said inked surface the area only of a sheet to be printed to which it is desired to apply the ink, and varying the degree of premure applied to different portions of said area to vary the tone of the color applied thereto.

7. In a printing press, the combination of a sheet of abrasive material, means for supporting said sheet, mechanism for inking the abrasive surface of said sheet, an overlay, and means supporting said overlay for movement toward and from said sheet, whereby a sheet of paper placed between said overlay and said abrasive sheet will be pressed against said abrasive surface by the overlay.

8. In a printing press, the combination of a chase, a plate mounted in said chase, a 10 sheet of sandpaper supported on the face of said plate, mechanism for inking the.

sanded surface of said sheet, a platen, and an overlay mounted on the platen of the GEORGE H. BROWN. 

